Resistance bulb thermostat



Judy @9 g V. @BEAM ET AL 2,403,843

RES IS TANGE BULB THERMOSTAT @horney Patented July 9, 1.946

RESISTANCE BULB THERMOSTAT Vilynn 0. Beam, Benjamin Cyr, and John M.

Wilson,

Minneapolis, Minn.,

assignors to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application November 3, 1943, Serial No. 508,839

2o Claims.

This invention relates to a temperature responsive device comprising a resistance element having a high temperature coecient of resist ance which is responsive to a change in a condition.

This invention relates specifically to a room thermostat comprising an electrical resistance element which has a high degree of sensitivity to change in a condition and which is provided with a baffle arrangement for guiding air in a tortuous path so that the rate of air movement through the thermostat remains substantially constant. Y

This vinvention further relates to a temperature responsive device and more particularly to a thermostat comprising a resistance element for use in the electrical measurement of the teniperature of air in a space.

This invention utilizes in a resistance thermostat a relatively long resistance element ofV high coefficient of resistance such as a iine wire which is open wound on different framework constructions and wherein a relatively high wattage is used, as compared to such a resistance unit for use with an ordinary direct current galvanometer type of instrument so as to obtain high sensitivity. Itis desired to have a considerable change in electrical characteristics or resistance` upon a relatively small change in temperature and Without any particular amount of lag, and to accomplish this, the relatively long resistance wire, the open winding, and the relatively high wattage must be utilized. The wattage employed in the resistance element is such that sufcient heat is generated as to actually provide a chimney effect. The difficulty in employing such an instrument is that the occurrence of unusual drafts, as perhaps the opening of a door, a person Walking close to the thermostat, or some other abnormal transient condition, will cause a response of the thermostat which does not represent an average condition of the air in a room. So as to eliminate such abnormal air disturbances, it has been found necessary to provide means to protect the sensitive element from the effects of such transient and abnormal conditions without materially aiiecting its normal sensitivity. In the present invention, different loaiile arrangements are utilized so that the response of the apparatus is not materially affected by a temporary change in the' rate of air movement at or near the thermostat. The balile arrangements are designed to slow down the rate of iiow of air through the thermostat. That is, the resistance element is so protected that it will give substantially the same response for a given temperature of air even though the rate of air movement near the thermostat is temporarily increased. Where the baffle arrangement is employed the air has to take a tortuous or circuitous path whereby the rate of air movement remains substantially constant even upon the occurrence of temporarily increased air movement in the neighborhood of the thermostat. These baffle arrangements might be said to provide means for damping the effects of variations in air velocity in the vicinity of the thermostat so that the thermostat responds not only to the general ambient temperature of the space in which it is located but also its response is governed by the general average air movement in the complete space as distinguished from any temporary abnormal transient air movements.

It is the primary object of our invention to provide an effective temperature responsive device such as a space thermostat of the resistance element type which is provided with a baiile housing for guiding air in a tortuous path or paths so that the rate of air movement remains substantially constant whereby the thermostat not only responds to the general ambient temperature of the space in which it is located but is responsive to the general average air movement in the complete space.

It is another object of this invention to provide a temperature responsive device having a resistance element which is a relatively long spirally Wound Wire.

It is another object oi this invention to provide a temperature responsive device having a resistance element which is a relatively long spirally Wound wire mounted on an open framework.

It is still another object of this invention to provide a thermostat comprising a resistance element having a high temperature coecient of resistance in which the temperature oi the ambient atmosphere regulates the flow of current through the resistance element.

It is still a further object of this invention to provide a resistance thermostat which has a considerable change in electrical characteristic or resistance upon a relatively small change in temperature without any particular amount of lag.

It is another'object of this invention to provide a resistance bulb thermostat which utilizes a relatively high wattage input.

Other and further objects Will become apparent upon a study of the specication and claims in conjunction with the accompanying drawings wherein are illustrated the preferred forms of our invention. y

Figure 1 is a front elevational view of a temperature responsive device with parts being broken away disclosing the resistance element wound on a frame member.

Figure 2 is a vertical sectional view taken on line 2-2 of Figure 1.

Figure 3 is a horizontal sectional view taken on line 3 3 of Figure 1.

Figure 4 is a front elevational View of a modified form of the resistance thermostat parts being broken away.

Figure 5 is a vertical sectional view taken on line 5-5 of Figure 4.

Figure 6 is a horizontal sectional view taken on line 6-6 of Figure 4.

Figure 1 is another modification of the resistanee thermostat disclosing a vertical elevational View of the front thereof, with parts being broken away, and

Figure 8 is a sectional view taken on line 8--8 of Figure '1.

Referring to the drawings in detail, 20 designates a resistance bulb thermostat as illustrated in Figures 1, 2, and 3. Thermostat 20 specifically comprises a iine spirally wound resistance wire element 22 of a high temperature coefiicient of resistance which is relatively long mounted horizontally on a pair of spaced-apart substantially triangular plastic leg members 24 having openings 2| and 23. A housing 28 comprising sides 34 and 36, a front portion 38, a back portion 4D, a bottom 2S, and an open top is spaced about the resistance element 22. The rear portion 40 of the housing 28 is secured to an insulation base plate 39 by screws 31. The triangular leg members 24 are secured by screw means 26 to the bottom 29 of the housing 28 and the leg members 24 are also secured by pin means 3| to a rectangular frame member 30 spaced above the top of the housing 28. The rectangular frame member 3|) is provided with an opening 25. The two triangular shaped leg members 24 are spaced at opposed sides of the rectangular frame member 30 and pins 35 aid in securing the triangular leg members together in spaced-apart relationship. Each of the leg members 24 has notches 32 on its front and rear surfaces in which the spirally wound resistance wire 22 is mounted.

A bafile member 44 is attached by screw means 45 to the insulation base plate 38 adjacent the top of the triangular leg members 24. This baffle member 44 comprises a top plate 46 and two depending intersecting anges 48 which divide the baille member into four substantially equal spaces. A metal shield 58 which is open at its top and bottom is located in the housing 28 and the shield 58 is secured at its top portion to the depending flanges 48 of the baie 44. The shield 50 is spaced from the triangular legs 24 which carries the resistance element 22, and the shield is also spaced from the bottom 28, sides 34 and 36, front portion 38 and rear portion 40 of the housing 28. Thus, there is a passageway 54 formed between the housing 28 and the metal shield 58 which communicates air of the room space with the bottom of the shield 50. The air thence rises over the resistance element 22 and emerges out through the open top of the shield 58.

Conductors 56 and 58 are connected respectively to the opposite ends of the spirally wound resistance wire 22 and lead from the resistance wire 22 through apertures 60 in the base plate 38 and the apertures communicate with channels 62 for receiving the conductors 56 and 58 respectively, which extend to terminal posts 64.

`Another form of the resistance thermostat is illustrated in Figures 4, 5, and 6. The thermostat comprises a spirally wound resistance wire 65 having a high temperature coefficient of resistance. There is a frame member of insulation material for mounting the resistance wire 65 comprising opposed sides 61 and three arm members 66, 68 and 18 which are secured between the opposed sides 61. One of the arms 66 is spaced between the lower central portion of the opposed sides 61, while the other two arms 68 and 10 are spaced between and adjacent the top of the opposed sides 61 with arm 68 adjacent the front portion of the opposed sides and the other arm 10 adjacent the back portion of the opposed sides 61. The bottom side of the lower arm 66 and the upper side of the two uppermost arms 68 and 18 have notches 69 so that the spirally wound wire can be mounted vertically on the three arms thus forming a triangular shaped resistance element with the apex at the bottom of the opposed sides 61. Baiiie member 12 is spaced above the top of the frame carrying the resistance wire 65 and comprises a right angular depending flange portion 14 which is secured by screw means 16 to a base or terminal plate 1|. A rectangular frame member 18 having an opening 19 extends substantially at right angles from the depending flange portion 14 and is spaced outwardly from and above the resistance element 65. The rear side 88 of the rectangular frame member 18 spaces the frame carrying the resistance element 65 from the base plate 1|. Rectangular frame member 18 has opposed dependin g ear members 82 which are attached to the opposed sides 61 of the insulation frame member. The frame member 18 also comprises depend ing flanges 8| and 83 at the front and rear portions, respectively. A metal shield member 84 open at the top and bottom is secured to the depending flanges 8| and 83 of the rectangular frame member 18. The metal shield member 84 is spaced from and surrounds the resistance element 65.

A housing 86 comprising a bottom 98, front side 88, and opposed sides 92, is spaced from the bottom, front and opposed sides of the shield 84. The bottom 8i! of the housing 88 fits into a groove 93 of the base 1|. The opposed sides 92 of the housing 86 are secured by screws 84 to the opposed sides of the base member 1|. The housing 85 is open at the top and is spaced below the rectangular frame member 18. This construction allows air to communicate with a passageway 85 between the housing 86 and the shield 84 and the air thus communicates with the bottom of the shield 84 and contacts the resistance wire 65. The air then travels up the inside of the shield 84 and over the resistance element 65, and then emerges out through the open top of the shield 84 to enter the room space.

Conductors 96 and 98 connect to the opposite ends of the spirally wound resistance wire 65 and respectively extend through apertures 9'! in the base plate 1| and connect respectively with terminals |08 and |82. These terminals |88 and |02 are adapted to be connected with an electrical circuit (not shown).

Figures 7 and 8 designate a third form of the resistance bulb thermostat which is designated as |04. The Y-shaped member |96 of insulation material is mounted within a shield member |88 comprising opposed sides l0, rear side I2, and a front portion |14. The shield |88 is open at its top and bottom. The arms of the Y-shaped frame member are spaced near the upper portion ofthe shield |88 with the leg portion extending toward the bottom thereof. The Y-shaped frame member |46 is spaced in the shield IGS so that the arms of the frame member are disposed adjacent the sides ||Ei and the leg portion being intermediate the sides IIB. The tip of the arms and the bottom of the leg member of the Y-shaped frame member i are notched as shown at IIS for mounting a fine spirally wound resistance wire ||3 having a high temperature coefficient of resistance thereon. The spirally wound resistance wire I3 is mounted vertically on the frame member IIIG and extends around the frame of the Y-shaped member ISB and only contacts the frame at the bottom end of the leg and the top of the arms. The V-shaped frame member Il' and the shield |08 are both secured to an insulation base member IIS by screw member |251.

A baille housing |24 comprising a front portion IZB, an upper portion |28, a bottom |3, and opposed sides |32 and |34 surrounds the shield member |63 and is spaced from the opposite sides Iiil and the open bottom and top of the shield. The portion |28 of the baille housing |24 is secured through a lug member |29 to the base or terminal panel IIB by screw means |3I. A groove |33 in the terminal plate IIS receives an edge of the bottom |30 of the housing |24 for securing this portion of the housing to the plate I I9. Each of the opposed sides |32 and |34 are spaced from the bottom i3d thereby forming openings iii and |38 into the baille housing |24. The opposed sides 32 and |34 of the baffle housing |24 have angular ilange members |40 and |42, respectively, spaced from the top portion |28 of the baille housing providing openings |44 and |46 in the opposed sides of the baille housing. The angular flanges |43 and |42 have a projecting portion |43 and |45, respectively.r The top |28 of the baille housing |24 has depending ilange members |48, Iil, and |52. Depending flange members |48 and |52 are respectively spaced from the angular ilange members |46 and |42 of the sides |32 and |34, respectively, of the baille housing |24. Shield member Hi8 has projecting members |54 and I which are spaced adjacent and secured to the projecting portions |43 and |45 of the angular langcs |40 and |42. Projecting member |54 is substantially intermediate the ilanges |43 and Itii, and projecting member |56 is spaced between flanges I5@ and |52. There is an angular bar member |58 comprising a base portion ISG and vertically projecting arms |552 and |64. Base portion ISii of the angular bar |53 is fastened to the bottom ISG of the baffle housing |24 byrivets or the like means |65, and the vertical members H22 and |64 are spaced intermediate the opposed. sides |352 and |34 of the baille housing and the opposite sides |||l of the shield member Hi8, respectively. The vertical members |62 and IM are respectively spaced from the angular members |44 and |42 of the opposed sides |32 and |34 of the baiile housing |24. Tortuous passageways are thus formed in the baille housing |24 and shield |38.. A tortuous passageway |66 is formed which extends between the side |32 and vertical member |62 of the angular bar |53, then over the top of the vertical element |52 and down between the vertical element I S2 and the adjacent side I0 of theshield Hi8, thence up through the shield ISB which supports the resistance element,then out of the top of shield |08 and over the projecting portion |54 of the shield and then out through the openingt |44. A similar tortuous passageway-|68 is formed 6 through the other side of the baffle housing |24 and shield |08 which communicates with the openings |38 and |46 at the bottom and top of the housing |24, respectively.

, In all of the thermostat devices disclosed in this application, the air is guided through tortuous paths in heat transfer relationship with the resistance element of the thermostat. Where the air is conducted indirectly to the resistance element, the temperature of the air is measured Very accurately, and there is no introduction of an anemometer elect.

Various changes and modiiications of this invention may occur to those who are skilled in the art, and we wish it to be understood that We intend to be limited only by the scope of the appended claims and not by the specific embodiments disclosed herein- We claim as our invention:

l. In a thermostatic device comprising a resistance element of high temperature coeiiicient of resistance, a frame member, the resistance element mounted on the frame member, means for guiding air in a tortuous path in heat transfer relationship with the resistance element, the resistance element being instantly and only responsive to the temperature of the Vair flowing through the tortuous means, and means for mounting the thermostatic device.

2. In a thermostatic device comprising a resistance element of high temperature coeilicient of resistance, a frame member, the resistance element being mounted on the frame member, and baille means for guiding air in heat transfer relationship with the resistance element whereby there is .a constant flow of air through the thermostatic device and the resistance element responsive only to the temperature of the air flowing through the baille means.

3. A thermostat comprising a resistance element of high temperature coeiiicient of resistance, an open frame member, the resistance element mounted in substantially non-contactual relationship on the frame member, a shield member surrounding the frame member carrying the resistance element, the shield member ybeing open at the top and bottom for guiding air in heat transfer relationship with the resistance element whereby the resistance element is responsive only to the temperature of the ambient air guided into heat transfer relationship with it.

4. A thermostat comprising a resistance elerment of Iine spirally wound wire having a high temperature eoeincient of resistance, ya frame member, the resistance element mounted on the frame member, a shield member surrounding the frame member carrying thel resistance element, the shield member being open at the top and bottom, a baille member mounted over the top of the shield member for preventing air currents affecting the resistance element, the shield and baille member guiding air in heat transfer relationship with the resistance element Whereby the resistance element is responsive to the temperature of the air flowing through the shield, and means for mounting the thermostat.

5. A thermostat comprising a resistance element of high temperature coelicient of resistance, a frame member, the resistance element mounted on the frame member, a shield member surrounding the frame member carrying the re- Sistanoe element, the shield member being open at the top and bottom, a baffle member mounted above the top of the shield member, an open top housing surrounding the shield member, the shield member, and housing member providing tortuous passageways for guiding air in heat transfer relationship with the resistance element whereby the resistance element is responsive only to the temperature of the air flowing past the resistance element.

6. In a, thermostatic device comprising a resistance element of high temperature coefficient of resistance, a frame member, the resistance element mounted on the frame member, a shield member surrounding the frame member carrying the resistance element, the shield member being open at the top and bottom, and a housing having an open top surrounding the shield member and being spaced from the shield member on all sides thereby providing tortuous passageways for guiding air in heat transfer relationship with the resistance element, and the resistance element being responsive to the temperature of the air owing past it.

7. In a thermostatic device comprising a sistance element of high temperature coefficient of resistance, frame member, the resistance element mounted on the frame member, and means comprising spaced apart elements providing cirouitous paths for guiding air in heat transfer relationship with the resistance element whereby the resistance element is responsive to the temperature of the air guided by it.

8. In a thermostatic device comprising a resistance element having high temperature coefficient of resistance, a. frame member, the resistance element mounted on the frame member, a baille housing surrounding the frame member carrying the resistance element providing tortuous passageways for guiding a constant flow of air in heat transfer relationship with the resistance element and the resistance element being responsive only to the temperature of the ambient air flowing past it.

9. In a thermostatio device comprising a tine spirally wound resistance Wire having high temperature coefficient oi resistance, a frame member, the resistance wire mounted on the frame member, a barile housing surrounding the frame member carrying the resistance wire providing tortuous passageways in. the housing whereby the resistance element is responsive to the average air movement of a space, and means for supporting the thermostatic device.

10. In a thermostatic device comprising a fine splrally wound resistance element having high temperature coeiiicient of resistance, a frame member, the resistance element mounted on the frame member, a baffle housing surrounding the frame member carrying the resistance element providing tcrtuous passageways in the housing for guiding air in heat transfer relationship with the resistance element whereby the resistance element is only responsive to the temperature of the air flowing by it, and means lfor supporting the thermcstatic device.

l1. In a thermostatic device comprising a .fine spirallt.7 wound resistance wire having high temperature cceiicient of resistance, Y-shaped frame member. the resistance wire mounted on the Y-shaped frame member providing a trian- Irrular shaped resistance unit whereby a relative- 1y large area of the resistance wire is exposed to air, a baiiie housing surrounding the frame member carrying the resistance wire providing tortuous passageways for the flow of air through the housing, and means for mounting the thermostatic device.

12. A thermostatic device comprising a resistance element of high temperature coeiicient of resistance, means for mounting the resistance element, and baffle means providing tortuous paths for guiding air in heat transfer relationship with the resistance element and the resistance element being responsive only to the temperature of the air flowing through the tortuous paths.

13. In a thermostat comprising a relatively long resistance element of ne spirally wound Wire having a high temperature coefficient of resistance, means for mounting the resistance element, and tortuous means for damping the effects of variations in air velocity of a space on the resistance element whereby the responsive element only responds to the average ambient temperature and average air movement in the space.

14. In a thermostat comprising a relatively long resistance element of ne spirally wound wire having a high temperature coeflicient of resistance, an open frame Work mounting the resistance element in Substantially non-contactual relationship, the resistance element having a relatively high wattage input, the resistance element having a relatively wide variation in resistance upon a small change in temperature, and means for moderating the effects of variations in air velocity in a space on the resistance element whereby the resistance element responds to the average air movement in the space.

15. A thermostat comprising a resistance element having high temperature coefhcient oi resistance, baffle means providing a tortuous path for guiding air in heat transfer relationship with the resistance element, and the resistance element being only responsive to the temperature of the air flowing through the tortuous path.

16. In a thermostat comprising a resistance element of high temperature coeicient oi resistance, a frame member mounting the resistance element in a substantially triangular-shaped unit, a shield open at the top and bottom surrounding the resistance element, an open top housing member spaced from the shield member providing a passageway between the shield and housing, the passageway between the housing and shield guiding air from the top of the housing to substantially the bottom thereof before the air enters the inside of the shield member at its bottom end for contacting the resistance element in heat transfer relationship, and the air finally passing out of the shield member at its top in close proximity to the point of entrance of the air into the housing member whereby the resistance element is only responsive to the temperature of the air flowing past it.

17. In a thermostat comprising a shield member, a resistance element of high temperature coefficient of resistance, a frame member comprising two spaced apart triangular-shaped legs, the triangular-shaped legs having their apex portions adjacent the bottom of the shield member, the frame member mounting the resistance element into a unit whereby the size of the resistance unit gradually increases from the bottom to the top of the shield, the shield member open at the top and bottom surrounding the resistance element, an open top housing member spaced from the shield member providing a passageway between the shield and housing, the passageway between the housing and shield guiding air from the top of the housing to substantially the bottom thereof before the air enters the inside of the shield member at its bottom for contacting the resistance element in heat transfer relationship, and the air nally passing out of the shield member at its top in close proximity to the point of entrance of the air into the housing member whereby the resistance element is only responsive to the temperature of the air owing past it.

18. In a thermostatic device comprising a resistance element of high temperature coeiiicient of resistance, a frame member, the resistance element mounted on the frame, means for guiding air in a tortuous path in heat transfer relationship with the resistance element, the resistance element being instantly and only responsive to the temperature of the air'flowing through the tortuous means.

'19. In a thermostatic device comprising a fine spirally wound resistance wire having high temperature coeiiicient of resistance, a frame. member mounting the resistance element in a substantially triangular shaped unit, a baiiie housing surrounding the frame member carrying the resistance Wire providing tortuous passageways for the ilow of air through the housing.

20. In a space thermostat comprising a resistance element of high temperature coeflicient of resistance, a frame member located over the top of the shield member, the shield member having communication with the baffle member, an open top housing member spaced from the shield and baie members providing a passageway between the shield and housing, the passageway between the housing and shield guiding air from the top of the housing to substantially the bottom thereof before the air enters the inside of the shield member at-its bottom end for contacting the resistance element in heat transfer relationship, the air emerging out of the top of the shield member into the balile member, then the air finally passing out of the baie member into the space in close proximity to the point of entrance of the air into the housing member whereby the resistance element is only responsive to the temperature of the air owing past it.

VILYNN O. BEAM.

BENJAMIN CYR.

JOHN M. WILSON. 

